The United Nations (UN) have developed a scale to look at sustainable development. Called the Human Development Index, it takes into account:
Life expectancy at birth.
Education - as measured by the adult literacy rates and the average number of years people spend in full-time education.
Standard of living as measured by 'Purchasing Power Parity'. This is a standardised measure of income which takes into account price differences between countries.
A mathematical formula is used to calculate the HDI and these are published each year by the United Nations. The graph shows the HDI for different countries, taken from the 2004 UN report.